Fire-box door



June: 24', 1930.

J. G. ROBINSON FIRE BOX DOOR Filed July 29, 1929 2 Sheets-Sheet l June 24, 193 J. G. ROBINSON FIRE BOX DOOR 2 Sheets-Sheet 2 Filed July 29, 1929 I m w v v) Patented June 24; 1930 ulN lranfs-raras PATENT omen; 1

7 application jfiied July 2a, 1929; Serial No. 381,763.

'16, are pivotally mounted on the door frame' at 17 and.l8 respectively and at their inner end .iave pivotal connection at 19' and '20 with links 21 and 22 respectivelyand the opv posits ends of said links are pivotally con nected to doors 3 and 2 at; 23 and 24.;respectively, It will be apparent thatq dow'naward movement 'of the 'PlStOIlfiQd; 1Q. through the connections" above described fiopenv the doors and'that its reverse movemen Will close them. I; r By means of a treadle 25 a'valve 26 may be actuated to establish andlcut ofiiwconn, munication between the main air reservoir on the locomotive, not shown, and the port 27 leadingto the space above the largepis-Y ton 8. The space between. the large and 7 small pistons, designated30, isnorina-lly in coinmunicatiolr with the main air reservoir through the port 28and passage 31,1aqi I check valve 29,being provided toflprevent flow of air. toward the reservoir through i said passage, A two-way valve 32 is pmvided' in the passage 31,5which valvein-ithe ,position' shown in 1 Figures 1 .ai 1d,3; permits g the communication above referred to; be tweenthe main reservoirand spaeefl30j between the pistons, The valve 32 may be s Figure 4; is a-view partly in horizontal .manually turned byendwise movementof sectionshowing the parts to which the in w q 33 Whlch plvotally e t t evention is 1 directly; applied. 9111134, the tt rfir 'n b g-rlgld y fixed to theplug of valve 32. Whenvalve3 21jis Figure 5 -is perspeo lve V f 7 ,7 t fiedtform of a plunger whichf formsipartt r 0t 110 1 .sh w rl gur -v l- I the space s cutoff fromcommunication 'ofthe' structure and'-F g f ;6,' T 8 a 4 s longitudinal 'andQtr'a S QI B, sect ons-sh tw h emam 3 IFQ Q T- ndl PhQ n communication ,Wlthll'le atmosphere through v: I V I I dig the modified plunger and its cooperating I g I I I port 35 thus subst tuting, atmospheric ,pres- {sure for; reservoir "pressure between; piss My invention is an improvement in power operated fire-box doorscsuch as are now in use upon locomotivesq The iimprovement relates more particul'arlyyto the type of apparatus described and illustrated in my co- 'pendingapplication for patent upon an 1m- 'provement in fire "boXQ doors,; Ser. No 380,117, filed July 22, 1929. Inxsaid copending application I hav'e descr bed the invention therein claimed inits appllcation to two-types of fire-box doors which are. now 'in use and known r'espectivelyfas the Shoemaker door andzthe Franklin door, to both-10f whichtypes of door the invention herein described is-in its broad'aspect also applicable. I v- I In the drawings. I i I L Figure 1 is a face view of a locomot ve fire-boxdoor of the Shoemaker type w th 20 my'invention applied thereto, parts being shown in section to moreclearly exhibit-the structure and operationrffl I I I Y Figure. 2 is an'enlarged detail View in elevation .and partly in; section showlng the 5 construction of anjoperating valve orcpet cock. v p v xFigureivis a sectionaljview st ll further enlarged of the plug ofthe pet cock.

sleeve; Figures -7 and being sections on line A A of Figure 6.5

i Referring first to Figure 1 of the dr aw- .ing, adoor ring or frame 1; I S- SQCHI'fEd lQQ thQ boiler endaround the door openlng, and

doors 2 and 8, meeting when, closed on line f'tons" M I In the normal positionof the partslflw itli 3 the doors closedyvalve 32 s in the position fSllQWIl IIIJFIg'LlI'G-l-WlthlBSGIVOlITPIQSSllI'Q s i, are pivoted at 5 and'6' to the door-ring. The pneumaticdoor operating motor comprises a differential cylinder 7 and cooper- "ating large and small rigidly; connected pistons 8 and 9. The piston'rod is 'pivotally connectedat 12 to lever-ill, which latter is pivotally connected: at 1-3 and--14 to levers. 15 and -16"respectively. The-levers la a nd between the pistons andatrnospheric pres,

; sure in. the space above the large pisto 8 which space is then in communication' iwithv the atmosphere through tl1e,foot,-valve,26, th s be ng the position of valve 26 when the treadle 25is. not depressed. I have not i shown the structureofvalve 26 or the pipes connecting 1t to the cylinder as this-construction is old and well known and asimi off communication between the space above I the large piston andi atmosphere and connects, that space with the main reservoir whereupon the preponderance of reservoir pressure on the upper sides of pist0ns8 and '9 over the pressure on the under side 01? pistonf8jmoves the pistons downward and opensthe doors, this movement bemg' cushf'ioned'bythefurther compression of the air in space i-ncident to its movement from fthe large bole to the small bore of the cylin- Yg' der. Upomrelease of the treadle 25 valve 26'returns to normal position thus exhaust- Ting the; spaceiab'olvethe large piston to the atmospherewhereupon the constantly maincloses the doors;

tained reservoir pressure in the space '30 betweenthepistons moves them upward and through the connecting links and levers I When it is desired to crack thejdoo-rs,

'i. "'e. 'open them partially or wholly and have 4 ing-"the tread-1e 25 depressed the rod 33 is them remain .in such p'osition'without keep- 'fp ushedl to the right as viewedin Figure 1 tion shown in Figures 1' and 3 to the position 1 fbloc-king reservoir air ;from. space 30 and thereb turning the pet cock from the posi- Sh Wn'inFigure'Q. "This has'the effect of exhausting the space 30between the pistons to the atmosphere, and as the treadle 25 is f left in its elevated position at this time the spaceabove the'l-a-rge piston '8 is also at at- ;moslpheric pressure. It willbefunderstood that-the lower endof the cylinder is open =-and hence there is alwaysatm'ospheric pressure-on the under side of the small piston 9.

Hence with the 'adjustment just described (the pistons and doorsarefree'from pressure ia'nd as the doors counterbalance each other they mayfbeffreely moved by handto any desired position and "will remain III' SIlCll ,l': -restorat1on of air pressure.

position until moved byfhand 'poweror by doors; and restore the arts "to position f for normal-opmrationf*by airpressure therod 33 ispulledto the left as viewed in Figure 1 thusrestoring valve -32-tothe position shown Figures 1 a nd l3 and causing the. pistons to risejbiy reason ofthe unbalanced reservoir pressure in space '30.

' Onejof-the objects of this -invention is to eliminate the da nger resulting from the occurrence :ofa blow-out when the doorsare "cracked, that is left partially-or wholly-open with air pressure cut off from the differ- V ential'cylinder as above described. In my copen dfing application above referfedto I describe means whereby the pressure in the V fire-box resulting from a blow-out, that is from the rupture of one of the boiler platesor tubes with resulting admission of steam tothe fire-box,-will instantly-restore valve 32 to the position shown in Figures 1 and 3' To accomplish the object described in'thc preceding paragraphI provide a bell-crank lever 38 pivoted at 40 on a bracket 44, the

bell crank being pivotally connectedfat. 37 to a. rod 36 which at its opposite end is pivotally connected to arm 34 of the pet cock at a point radially 'outward from the v connection of rod 33 therewith. The other end of the bell crank is provided at: 39 with a pin which engages a slot'43fin the'rod 42 upon the end of which is mounted a pressure member consisting ;of a .plunger or piston: 41'having a sliding fiti'n sleeve 45 which extends through" and is welded to boilerplates 46 and 47-thereby forming a cylindrical opening extending from the in- }terior to the exterior of the fire-box; The V movementof the plunger 41 in the sleeve 45 1 may "be. limited by stops 48, .49, assembly;

being permitted by welding one of these stops in place after the plunger is inserted in the sleeve a11d-the distance between the stops being suflicientto permit the extent of movement of the plunger necessary tof.

perform its function. In order to dispense with the necessity-of weldingla; stop uponthe sleeve at the time of assembling the sleeve and plungen'thesc parts may: beconstructed as shown in Figures 5., 6,17 .and 8. In this form the flange 48' (Figure 16). is similar to the flange 48shown in Figure 4,- and may "be formed when'the sleeve 45. manufactured. The flange at the opposite end of the sleeve 45' isi'discontinuous, being formed in two opposite segments 70, 71.each

or '90 degrees "extent shown in lFigure 7, j 7 1' which is a section through the sleeve -on"line*"-' 'A.A or Figured" In F-igure8 I show the 7 cross section of the plunger 41" adapted to; To close the .115 cooperate with thesleeve shown 'in'Figi-rrel 7 and having opposite quadrants 72, 73 of.

the full; diameter of the interior or the sleeve and the intervening quadrants sufficiently less injdiam'eter to .just clear-f the inner, edges of the segmentalfianges 70, 7 1 of the sleevcJ In assemblage the it with the segmental flanges 70, 71 in which latter position the plunger ,will be held 7 against rotation by its connection with the bell crank lever 48. In the structure forming the subject of the invention claimed herein the length of the slot 43 in plungerrod 42 is a little less than the length of the 3 movement imparted to pin' 39 of the bell crank when the rod 33Eis pushed over to turn valve 32 to the position shown in Fig-- -ure 2'preparatory to cracking the doors, the' effect of which is to permit the valve'to be turned freely and without moving plunger 41. until the last part of the movement whereupon pin 39 contactswith the inner end of slot 43 and imparts a short movement to the plunger. I have indicated at 39 the position of pin 39 when the valve has been given its limit of movement and it will" be seen that in order to arrive at this position a slight movement must be imparted to plunger 41 by contact of pin 3,9fwith the end of slot 43. Stop 48 is positioned to permit this movement. \Vhen the rod 33 is pulled to the left to .restore' valve 32 to normal operating position the pin 39 of the bell crank will move freely in the slot 43 until near the end of. its movement when it will contact the outer end of slot 43 and] move plunger 41 a shortdistance outward.

In my copending application above referred to-I showed two modifications similar generally to the construction above described, but differing, in that in one form there was no lost motion between the'bell crank and plunger rod 42 and in the other form the amount of lost motion was sufficient to permit operation of valve 32 tion'of valve 32 in order to eliminate the:

- possibility of the plunger being rendered immovable by the lodgment of coal dust and other foreign matter as might occur if it were permitted to remain stationary relative to the sleeve. I I I There is also the possibility of the plunger being. moved relative to the sleeve by the shocks imposed upon the. locomotive in coupling and uncoupling cars. The outward movement of the plunger caused by the pressure of a blow-out in the fire-box moves the 7 bell crank in the direction which restores the pet cook 32 to the position shown in Figures 1 and 3, thus closin'g'the "doors and ac,com plishing the intended purpose; (Should a shock upon the locomotive occurring when the doors are cracked cause the plunger to move outward thedoors would likewise be H5 moved from cracked to closed position, but

as this is something that would seldom occur 'and would cause no lnconvenlence other than the necessity of again cracking the doors no I preventive measure is necessary. But if with the doors closed a shock upon the loco- 'motive-"should cause excess inward 'movee ment of the plunger the effect would be to cut off the reservoir air" supply from "the space30 between the pistons 8 and 9. Ifthe fireman should then depress the treadleto open the doors the resulting admission of reservoir air to the space above the large piston 8 would drive the pistonsdownward and open the doors, but with considerable violence due to the absence of air under reservoir pressure in the space between" the pistons. Upon releasing the treadle the doors would remainopen' as the presence of air under reservoir pressure in the space 30 1s necessary to effect the closing movement.

Under these conditions the structuretherefore would become inoperative. In order to preventth'e' -condition described from arising I place the stop 48 at the inner end of sleeve in such a position as to prevent the plunger 41' moving inwardly far enough from the position shown in Figure 4-toturn the bell crank 38 far enough to alter the effective position of the pet cook 32. In order to permit the pet cook 32 to be rotated a short distance without impeding the flow ofreservoir air to the space 30 I preferably slightly flare or countersink the ends of the port 60 in the plug of the pet cockas indi-- cated at 61 and 62, shown most clearly in Figure 3. V i

-I claim as my invention:

1. In a boiler firebox, a door, door operatin trgllable' by the operator for opening and in open position, means operable by pressure within the fire-box occurring when said door is retained in open position for returning said door to closed position, said last named means comprising a pressure member exposed on one side to the interior of the firebox and having a lost 'motion connection 7 with said door operating mechanism, said 1' sion between the connected members .ofa" .part only of their movement. l

lost motion connection permitting transmis- :S 2.' In a boiler fire-box, a door,afluid pressure cylmder for operating said door, a valve for establishing free communication between mechanism comprising means coni 105 7 closing said door and for retaining said door; 7

lie

said cylinder and theatmosphere in orderf that said doormaybe moved to and left in i open or partially open position, a pressure member exposed on its innerside to the p'ressure within the fire-box, a lost motion con nection between said pressure member and said valve, the extent of lost motion in said connection being sufficient to permit the major part of the movement :of said valve to take place without communicating movement to said pressure member and tolimit' the transmitted movement to that taking a place adjacent theends of the movement of the valve. V 1 I 5 3. In a boiler fire-box, a door, a fluid pressure cylinder for operating said door, an admission and exhaust valve in said fluid pressure cylinder, an open-ended cylinder extending from the interior to the exterior of said fire-box, a plunger having a sliding :fit in said open-ended cylinder, a, lost motion 7 connection between said plunger and valve, the extent of lost-motion being suflicient to permit only a relatively small partof the 315 movement of said valve to be transmitted co said plunger, outward movement of -said plunger under pressure ithin thefire-box acting tomove said valve to the positionin hich pressure fluid is admitted to said cylinder. T V Signed at Chicago, Ill. this 27th day of V "July,1929. I JAY G. ROBINSON. 

